SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab0c7b0fcfaabe4b17a941e95ef6f6694c08b11e50f8c2d1a153b6262da92ae0' 
  AND token = 'irN2ClRWkTcu0yogIy8C8Luux1+eN3ObPHyOGC6WDmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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