SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af520307daf7216cd5f068d57d929105ff70e50d4d5ca80c12bc337a3a093086' 
  AND token = 'NgPl8XLOwaLonMV9VtorBmCG6mMq53RzwluTy6sLT1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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