SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98c4be1aae81e5986da7ee9d3e9acce27a1f170ba077b9555d113929a93e795d' 
  AND token = 'L9wBgRHslZzHLBNFTQWTIZaurFnCfnIIoksifzYFkf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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