SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e9562c2fdc2302234bec06166be0fd4c7395aa19737fd762d34e816355f5ef4' 
  AND token = 'pu0RL2A48JCKY4LyDgAREBjjKARTB91wLdccprbaZ+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}