SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa4986e90e71a68ef5a77589423d7313f14753f1f0a19e2bb18c90e0b020d94a' 
  AND token = 'td1RwrjF7Dg+CQZBvnD0IW8mDJ/eJRFo08E8Cg/W3gA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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