SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '966da2630c6291e7fefbf78f8929009f19318c50d916f253ee14bf75d1fec14b' 
  AND token = 'rXGGpB5RaUqRlp+1OKBFWmtYKG8TD1j86nsN3ut2/9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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