SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b648b0a6dbcee2751ea91055416070e3232d9cefc720cc398210b7b7eb486bda' 
  AND token = 'uzwMf78PJ5fRvRYZmE8gTBGtvuUBUtCaS9XfnUCJskQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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