SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd87e00559638416995e0b0ef0a7e1d14612d3c07ad415db1e15c844203ddd97e' 
  AND token = 'UhXZTlldrv3OuO+j3z3FXqFRkrFwx63jXhm/PEAGUUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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