SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be1773ca3bace810667a6d31183aacd580382be5f04d1781a5c6f440c993c341' 
  AND token = 'COqbfjIJ8UWXTJzp+OTv7u+20hIvRORb5bm7YB64Bp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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