SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3359f79bf494c3c555e66bed9b42ac417021b2f79698c55e6d37d59cb8b5f2a5' 
  AND token = 'pjs6phBXGJVLA5dz1wAI1x4X+PHFo6UQAFAzgR0FCdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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