SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f966711032602d08b0ff697ad7d7d9bd31e5c447a0c37f69c9efa2fba8cf0d6' 
  AND token = '7qsEmt4Lezhh+ebVJ1YUCFPvenp1LS0xgWvJs42v3l0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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