SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56875f109a91be6670b9f4ee3fa2efc7082f60d5f943eef76c3e3423272bd144' 
  AND token = 'vND0bE5Ncb2uLK24JCNknewH0nR52nQttl9wDqfY+ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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