SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1400045512ba122dab18893fe4145e15ea38a25384f81d292df8c20d2da85447' 
  AND token = 'ah2PVB75TF25w4Px2sihvqd1Yr+Vcko1tzfVSt9vr7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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