SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f7b27cee42f513565ae458e2f5a2deca210fdc69e25514b47f870bf1068d8e1' 
  AND token = 'fseWHdA1XvkkxM5qtTixc5wyBITQF2h0dSrnLp3/PGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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