SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5a2ed0ca308627f78254be4a5b24a516fa2cf3b18451a2787aeb897c39876d5' 
  AND token = 'jugEVzVFXFGt+wpFnz0d/tLy/fAh3a4iN1sUECUuhgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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