SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acc32c576ff13dbe9190f3a591e108cacb53a5d0db027229d614380ddd2759d8' 
  AND token = 'SX9ihpNAkGRTA+cZ3gMn4A8NUG+4hngGLNNzgJG+glo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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