SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c6624b2115927aea520cd5c1fc5460d7ca867a801fbfcd407f36ce76de1a3a' 
  AND token = 'CV3bSdmhp11qZkVP4tPZP7TyH78ZjPQFg5JU474xOG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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