SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a45821a9867355cbf77380487bb27dd932b8ec920080fbcad3fb42657e088461' 
  AND token = 'j4Lxl9SUE78xtktkgZTl8Y9twVTDTBZkQ7liBLZvGiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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