SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a1bf6e1bc65673c47abcba23ca076104ec60482d1f545d57b0715f4ef586276' 
  AND token = 'vovatjnh1vbUpo6/w9tW4jm0vtYcD2WHo4vJWpEFeIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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