SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f8105efeb7027d2821c31766754100b5ce230a24ce0bb862c2f7fb840a5ddc3' 
  AND token = 'vqBzLv9HUYxEaUeq5LzQz/AKwk/st/Hw+MBP2w6NKh4=' 
  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"
    }
  }
}