SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bbf991287c1078d843246adbbfc8dcbf117621f30acaa88e3247d0be4026a15' 
  AND token = 'hXpUjgsTBcTRu7i//HQRHs79ip2FsQzzdsUXLoSGLmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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