SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f693bb486a4dec3f16abf093f8153f747919058a540f83439f2d02115245c0eb' 
  AND token = 'F1SXgtMy0jTm2uTtcgVOAwfmZzLzvD7ArQWO1Nn0Y08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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