SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54db0fdb97ea4d165bd1748fae518c160886034961664efe242bbc70040bf4d8' 
  AND token = 'PjNaLify4CmPB5q1fCTB+cElKoIzF3j2bR3KoGiNH7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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