SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '940063a45447af7eb7ed387697fdd9de3048c2341e68abddd79424ff8338eaed' 
  AND token = 's4aCc0q1idon61X4/bTJAjUDnufCLKgz2/5Edp1h8GM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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