SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4750380d23a3e73a7cdd1c79d213a9709c561b19db7c1a2d5ba4edb8b6824c8c' 
  AND token = 'yD2TH5PLpdPrHf+4VNaXce2tlR1+QHAyvCXBTGwZgr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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