SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81415b2b544014f0af4dcd2ade5541f944d1f8b82e29e54c72fcc0665673d18d' 
  AND token = 'nF80SWUP3mprQ5Mu9acfv+7a+6DdifWsefNRZGb5t+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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