SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd890b975338ba3d135b6eae58181709af4e22d9c2b449897126634d9540c5ea9' 
  AND token = 'bezRK/N6sVuYOA9laI1TVPEWZ5kWt9X6FXSRhBeW27g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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