SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b49967a8c6fd0afb8b775577304de81aad7b101113af583f5e1052e2d1c2c516' 
  AND token = '/8jv0YExBofqLvfJkzJNy+Kn//JCzqWDi+Col7LCJyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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