SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f338d8dfad24104a767a6abcc3a55e6962a069a32091a32db6e67249442a2d6d' 
  AND token = '4BcDk1JKsG7eCoEGUMBOIu2sFYSWTvNlexuDx5n51lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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