SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d65e3c67353192f8749998204463812acda77e5637b796578d4b294ec4206c6' 
  AND token = 'O6awGaLlT+V2X/xgNo1VskHE2dyBeLXEXaopoLHGj7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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