SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c439e59957747c80db6526a0db0cd5383d9d1be2d315753bccdc1ef50375b22' 
  AND token = 'lc4L76xC3z/g9msyaalrNglTYAgdgkGbETtHw4fGmHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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