SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eaf953c77419f542560cb2917ebde1c17cfa708d0f5bcb4ae73806262c0b507' 
  AND token = 'fCUYOtZdeX4smumSF6XW3B8s46WqY9njweX/Bf+DXEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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