SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb147bdb5e3d2e84ac997557b93e271e971e328c425f9ee1499c711cc4155697' 
  AND token = 'KQlbFR0T8JRrTd3sCQUnaKIao2gzDaTsxv/eDlykWg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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