SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0637bff8c00fac10b1478952042f41dc4dd71dadcbd3f5c537a526af22066b8' 
  AND token = 'gqyTRyKmZBOQY+JaS6PBomrYZNUsK7eyGGIGM6IqRrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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