SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c11f18cf68cc4c983a1549edaad1c99a68c774cab9fa8bd488aceb9884d71325' 
  AND token = 'Zfx/ykuZAN9aAn/aJw9ojAxZdt6eGvI6ce5RKXUPeiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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