SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fd9fa988025144fe26c8e877f3026288631fdd5442441e8c42ba5c9d3133fc1' 
  AND token = 'F6a0uWQD5CHQYripVQ2Rs4IBovGOFOeUR/2LMUeccw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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