SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ea42b23f9af241b7384ed8c56b719f3aead18c34c6916780168bdb5b6c73088' 
  AND token = '/GGTJmu8qQR5Fu+4fcDHHJ9brJOpVDi1L91jH7ghw9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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