SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1417b9045ba3989f6f3620cc2dc2b9928e9afbac9911174a310321e2c91f527' 
  AND token = 'cMIHjhyMaqa6PTOKYK5+TZjhH9rdgVtGZJtrz/HU5Kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}