SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8d0f53b4fdcc025c05c610c16475643c7b21a0bdc28967765ab46012f1779f0' 
  AND token = 'c7FsYdGmk5Lm8sCkMKoygF8/p78/afIxIyilWSXtKfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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