SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e3fb6979f47176e77fb94bb2ae97bd61f1c94627453f60596b38f47c2275778' 
  AND token = '7PKckGRjzRCihWsYDAwzB1rZMLlJVYB0MmEEU8Yts6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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