SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07bb4fcf1256839b666d01be954a0661dfcdfa8ea92fdde165d2a49c3f400aa1' 
  AND token = 'R0srmkmvFX+xzy4CVSV5BjaytmjRfXQ1RqRtJNtZCwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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