SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caa4650013b9f5a35ba731b80a082c9178da0e3d44ea2d4010c62e31dfeebb02' 
  AND token = 'jRGR495haUQHvs7g4mwuYlNgyuqBwLpCTXYkvAiV+RE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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