SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77741f548be4e0731929c6fa87e107a221954ec142a580184f3bab9c94bfd6a3' 
  AND token = 'hKCzZGRixUm8ABYvyMpBztvUpFKyJzrbrpbL5tOHXS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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