SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3781d79ec507266fe583e6338e29818ee257244a990c9800806ca9f6160bf85c' 
  AND token = 'pXdYGIs0O+Qgz+KI4qRU9Me7gmQyqwTRBnoikjq6D/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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