SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd791724d9613e582105f29b043a8b4b1d86d8a0bb4055ecca3c0ec0fa9115c7' 
  AND token = 'OxhfhjWrEjs/2DYOaJc1NDmXXjEKAHskCzZaRXbRpGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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