SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e0fcb6fa2ccf7a2bc34cd892ad75bc512b6a5e14d15897c94187c5bdbfcb0b7' 
  AND token = '7tfvv3gw4n8CmqSuGTdgFW+1UuYroGgCGaiOTJ9DcXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}