SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19a68c58e71324709f5e36a6b8ca5e2eef88170d07d6edbef17e624e23df3530' 
  AND token = '3cX1Npqzzb64ZWuj6N8Epbw8aAhs70AcMyX2M3hiT8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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