SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a970c5d8c2a16e172a8949217fde9eec9d5d3f2701f83753c35096ab485909b' 
  AND token = 'T2itUrTVvSznGEKpqGORuVRN0ViwQa+G4AWFpmq+P1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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