SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c000dc3097d5cda57e4912b3f46731d0223da950cdf92bcd7522dcd45ee63989' 
  AND token = 'm0i4BIHjsVGADJzd8QAYcCta1JEy6s/jcfv1ugnrFDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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