SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0242b5f6d78c153f002a7e9d62fa830f50e58f1f62189d9258b6f36d18069dc' 
  AND token = 'BSLDmrziOs1vhLLHF0PVWwNqmXwWpjvg0Ke+716XrdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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