SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7d14df3ee662449e4a805e691a922bdd90793206b582c825c1332cfe152c3cb' 
  AND token = 'n2MrWSuSgSfNuZAvpaDRu8+bGnJnzPDUV3JAu0x+1Os=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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