SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d5322bd2db0a9449fe4d5bf28add4168fa0d3ae49dfb4e36d80ca6ea78b640a' 
  AND token = 'tDPlggl3JB0M5chmHdV1dHY50+fkOHgjU1DQ368BVg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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