SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '555b367a1b685e597210d56e7a20e48068a477069deab017852c3ca58145efe4' 
  AND token = '+VBaUFxgyfRozCIF7N5b0Wv8IBDcgJOqBLZbY+7/aho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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