SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b27703465d60ef0715320ae6addaaa5ef3df07e32623a8b2cbb529899dd334d6' 
  AND token = 'PEl1BKnoVRJ+vk4TzSfPEgcZFqAxYL8fsxZ4ritbwBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00074

JSON explain

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