SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '309fd2a1f6b25df5ccee31441c5d13a9c1f3fd85092c3cf998db6939b019eeec' 
  AND token = '/ZZMLoX59AAnn86TU5qGywzN4VBqJn2z8WBSAHg2QgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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