SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9516c85b7ce32cc3c39cfbbdfb43d88db3832e253cb16e734a30bb626cb977f' 
  AND token = 'F3Cul1mTFeh5dgir88BzW7OExf5P3Z9ZLu0mM7ULDDk=' 
  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"
    }
  }
}