SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edd704e34979c77868015664a0bc3c1ffeff05cbb48b1b9a7310d699635f9e59' 
  AND token = 'Po393ehAtHpL6EHliSS6cMgU9JlyMpARq/FRdQUn218=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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